Backup filters

As documented in the Backup article, if there are no changes to the config of your device, a new "backup" point is not required. In effect, this means that rather than showing you individual backups, NCM will show you configuration points - ranges of valid configurations on your device to build a configuration timeline of the device. To be able to do this, NCM needs to be able to figure out if there was a config change on the device. For example, if the configuration of the device contains a timestamp (Cisco IOS will show the current timestamp of when "show running-config" was executed), this needs to be ignored so this "change" in the configuration contents doesn't create a new configuration point. NCM contains many built-in filters for such dynamic data (as mentioned in the Backup article), but you can also create your own custom filters for backup contents.

Filtering order:

• "Deleted data" filters

• Built-in "dynamic content filters"

• "Ignored data" filters

Ignored data filters

The "Ignored filters" can be used to ignore changes to parts of the backup - during comparison of the new backup to the currently stored backup, NCM will IGNORE the matched data for the comparison purposes. The data will still be stored as a part of the backup, but if changes in the data happen, those changes will be ignored.

Deleted data filters

The "Deleted data" filters can be used to completely remove parts of the backup - before comparison of the new backup to the currently stored backup, NCM will REMOVE the matched data from the "new" backup. This means that this data will not be stored as a part of the backup at all - as if this data was not received from the device at all.

Filtering types

Line filters

For the line filters ("Line starts with" and "Line ends with"), if there is a match, the whole line is filtered / deleted.

These filters can be used for simple and easy matching rules if you know the exact beginning or ending of a line you want to filter / delete.

Regex filters

If there are no capture groups in the regex, the whole regex match is filtered / deleted. However if you use capture groups, only the content captured by the capture groups will be filtered / deleted.

This allows for very precise and flexible matching using regex and capture groups, so you can filter / delete only exactly what you need.